Vine movement towards support

creatrix(z7 VA)April 14, 2005

I have a small recently rooted ivy plant. It's growing vertically, and I turn it once a week or so. Ok, I know the leaves move towards the window for light, the cells on the dark side get longer than the sunny side ones. I understand that wind movement and touching a plant 'causes'a sturdier stem- ? hormone stimulation.

I put a taller plant behind the ivy three weeks ago, and haven't turned the ivy since. The taller plant is 6 inches or so from the ivy. How did the ivy know to grow away from the light and over to the support that is 6" away? Air current changes? Electromagnetic fields? Intuition? Magic?

Climbing vines need to find a suitable support on which to grow. Plant parts in need of suppoprt begin what appears to be a hunting motion whereby shoot tips rotate in a nutational movement. This is a mechanism that helps plants find needed support in their attempt to reach optimim light. When the shoot rubs against a support, the rubbing induces another response called a thigmotropic response (induced by touch), in which usually the shoot usually begins to curl around the support. Of course, vines typically show the most extreme nutational movements.

So, if you're convinced you're not seeing phototropism in action, I would bet that you are seeing initial stages of nutation.